Classified sites are very popular and generated a huge traffic. Offering to their clients visibility options and anonymization tool are the two main axes of their monetization strategy.
Building a community up is the first step of every social network, starting monetizing it by offering added value services is one of the keys of their success (subcription and customizable payment API).
The aim is to collect information and to deliver them to the end users. Specific directory sites have risen (e-reputation, popularity forums…). DNA is the perfect solution to monetize these services.